Novel Viral Based Approach for Tracing and Optogenetic Manipulation of Specific Neural CircuitsName : Dr. David C. Lyon
Affliation : Associate Professor And Vice-Chair, Director of Graduate Studies
University : University of California
Country : USA
At the cellular level neocortex is comprised of a dense population of excitatory neurons and a more sparsely distributed array of inhibitory neurons. While representing only 20% of the cortical population, inhibitory neurons provide an influential gain control that works under a myriad of conditions. In primary visual cortex, for example, inhibition is essential for refining several basic functional characteristics, including preferences for stimulus contrast, size, and orientation. Multiple inhibitory neuron sub-types have been described and are now being studied in great detail in transgenic mouse models. However, investigation of any inhibitory neuron subtype in non-transgenic mammals with more complex visual systems remains elusive. To address this, we recently developed the use of cell type specific promoters in neurotropic viruses that can be used to effectively target inhibitory neurons. In this way, we are able to selectively deliver receptor genes used for a second virus, a genetically modified rabies virus, which can be used to trace the direct inputs of the specific inhibitory cell types through a fluorescent reporter, and to deliver genes used for optogenetic manipulation. Through this novel approach we are able to determine for the first time in higher visual mammals how the functional specificity of inhibitory neurons relates to their complex network of cortical inputs. While our goal is to understand inhibitory neuron function in visual cortex of species with highly evolved visual systems, this technique will be available to others for use in any mammalian species and any region of neocortex.
David Lyon is an Associate Professor and Vice-Chair of the Department of Anatomy and Neurobiology in the School of Medicine at the University of California, Irvine. He received his Ph. D. from Vanderbilt University. He then received postdoctoral training at MIT followed by the Salk Institute for Biological Studies.